Approaches of the materials evaluation and strength design for bearings based on the growth resistance of a shear-mode, small fatigue crack

轴承的失效是由滚动疲劳引起的剥落，即表面分层引起的。在本研究中，定量研究了尺寸小于1mm的剪切型疲劳裂纹的行为，这对轴承的强度起主导作用。结果证实，日本主要使用的马氏体组织与欧洲常用的贝氏体组织在强度上没有显著差异。此外，还揭示了裂纹面的干涉对剪切型裂纹扩展起着很大的阻力作用，并提出了新的强度设计公式。

The failure of bearings is caused by flaking, i.e. surface delamination, due to rolling fatigue. In this study, the bahavior of the shear-mode fatigue cracks smaller than 1 mm in size was quantitatively investigated, which dominates the strength of bearings. As a result, it was confirmed that there was no significant difference of strength between the martensite structure used mainly in Japan and the bainite structure used commonly in Europe. In addition, It was revealed that the interference of crack faces acted largely as a resisting force for shear-mode crack propagation, and an equation for a new strength design was proposed.